Attic ventilation systems are typically used in residential buildings to provide proper ventilation of the attic space, which is desired to help prevent formation of condensation along the interior surface of the roof. Condensation can damage the attic insulation and the wooden structure of the building itself. Proper ventilation also helps to prevent premature melting of snow accumulated on a building roof, which can lead to the formation of ice on the roof that presents a safety hazard and can also lead to roof damage. Such attic ventilation systems will utilize vents placed into the underside of the soffit, which projects outwardly from the roof of the building and forms the overhang at the perimeter of the building roof. The intent of these attic ventilation systems is for air to travel through the soffit vents into the attic space and be discharged through an attic vent, which is typically placed at the apex of the roof.
The use of insulation in the attic to provide a barrier to the transmission of heat between the occupied portion of the building structure and the unoccupied attic portion of the building can restrict, or even prevent, the flow of air from the soffits to the roof vent at the apex of the roof. The insulation can be packed along the joists of the roof trusses to the soffits and not allow a passageway for the movement of air past the insulation into the portion of the attic above the insulation. Known construction of the insulation material can include cellulose, rock wool, fiberglass and expanded foam, the latter being used most often in manufactured housing, i.e. housing constructed in a factory and transported to the job site instead of being constructed at the job site. To maintain a discrete passageway for the movement of from the soffit, past the insulation barrier, and into the upper portion of the attic for discharge through the roof vent, baffle vents have been provided for attachment to the interior side of the roof to keep the insulation separated from the interior surface of the roof deck.
One embodiment of a baffle vent can be seen in U.S. Pat. No. 7,094,145, granted on Aug. 22, 2006, to Palle Rye, et al, and assigned to Brentwood Industries, Inc. The Rye baffle vent is stapled to the interior surface of the roof sheeting between the roof rafters and includes a tail portion that is bent in the vicinity of the soffit to form an insulation block that extends from the interior surface of the roof sheeting to engage the wall top plate. This baffle vent thus forms a barrier that prevents the movement of insulation into the soffit area and restricting the flow of air from the soffit into the attic. The structure of the baffle vent incorporates a series of convolution that are oriented parallel to the roof rafters to provide channels that define passageways for the movement of air past the insulation that is engaged against the baffle vent. In operation, the baffle vent utilizes the channels to keep the insulation away from the interior surface of the roof and establishes dedicated passages for the flow of air past the insulation along the interior surface of the roof sheeting.
Earlier configurations of baffle vents can be seen in U.S. Pat. No. 4,446,661, granted to Jan Jonsson, et al, on May 8, 1984, in which a corrugated sheet is fastened to the vertical surfaces of adjacent roof rafters to provide a plurality of longitudinally extending passageways for the movement of air past insulation in the roof. A major consideration in the design and manufacture of such baffle vents is the cost of such structures, particularly when taking into consideration the large square footage of the roofs of some residential buildings. Consequently, baffle vents have been fabricated extensively of foam or plastic material in narrow sheets that form self-supporting structures that can be handled and manipulated into position between the roof rafters for attachment against the interior surface of the roof sheeting. In U.S. Pat. No. 5,341,612, issued to Gary Robbins on Aug. 30, 1994, a baffle vent structure is formed of a thinner foam sheet material and includes a reinforced structure to prevent the vents from collapsing during shipping, handling and installation, as well as to prevent collapsing of the vents from compacted insulation which often is blown into attic areas of a building against the underside of the baffle vents.
Conventional residential construction affected at the job site will typically have the roof structure formed at the same time as the exterior shell of the building so as to get the building under roof to prevent the intrusion of foul weather into the interior of the building. The baffle vents described above are intended for use in such on-site construction techniques. Since the insulation is placed into the attic area long after the roof sheeting and shingles are added to the roof rafters, the baffle vents are formed to be placed between the roof rafters on the underside of the roof sheeting by attaching mounting flanged to either the vertical surfaces of the roof rafters, as is depicted in the aforementioned U.S. Pat. No. 4,446,661 to Jonsson, or the underside of the roof sheeting, as is depicted in U.S. Pat. No. 5,341,612 to Robbins. Generally, the baffle vents are installed as part of the installation of the insulation by contractors that specialize in the installation of insulation, rather than by the roofing contractor that will install the roof vent at the apex of the roof structure.
Manufactured housing is constructed in a factory setting where there is no pressing need to have the roof structure completed before the interior portions of the house are completed. As a result, the baffle vents can be installed on top of the roof rafters before the roof sheeting is fastened to the roof rafters. Generally, manufactured housing is formed with the interior drywall sheeting applied to the bottom side of the ceiling joists to form the inside ceiling of the housing before the roof is completed. The roof sheeting is then attached to the top surfaces of the roof rafters, followed by the application of the exterior roofing materials, typically fiberglass shingles. Insulation can then be installed between the joists on top of the drywall. While blanket fiberglass insulation or blown loose cellulose or fiberglass insulation can be used, expanded foam is often used in manufactured housing construction. The expansion rate of the foam places a substantial pressure on the baffle vent and will often collapse the passageways, resulting in the interruption of the air flow from the soffit past the insulation layer.
Blocking the opening between the joists and extending vertically from the wall top plate to the baffle vent beneath the roof sheeting is important to prevent the intrusion of insulation, particularly blown insulation or expanded foam insulation, into the soffit area, which would restrict the flow of ventilation air into the baffle vent for passage into the attic above the insulation blanket. In the manufactured housing industry, the insulation block is typically formed by rolling blanket fiberglass insulation material and stuffing the roll between the joists at the vicinity of the wall top plate. The baffle vent is then placed between the rafters before the insulation is blown in or expanded foam is injected into the area between the joists.
An example of a baffle vent that is adapted for use in the manufactured housing setting can be found in U.S. Pat. No. 5,596,847, granted to Michael Stephenson on Jan. 28, 1997. This baffle vent is formed with longitudinally extending ribs that are spaced on eight inch centers so that the single panel can be used on rafters whether spaced sixteen or twenty-four inches apart. A score line is formed on one of the interior ribs so that the excess eight inch strip can be removed if the baffle vent is used on rafters spaced at sixteen inched. In U.S. Pat. No. 4,096,790, issued on Jun. 27, 1978, to Laurence Curran, the baffle vent is formed to span across multiple roof rafters with a panel hanging down to engaged the wall top plate and form a barrier to restrict the passage of insulation into the soffit area. In the Curran baffle vent configuration, mounting ribs are spaced at intervals corresponding to the roof rafter structure on which the baffle vent is to be applied. Thus, to be used with sixteen inch and twenty-four inch rafter spacings, the Curran baffle vent would have to be provided in two different models.
The Stephenson baffle vent configuration, and particularly in the Curran baffle vent configuration, the spacing of the longitudinally extending ribs provides a wide span between the ribs to define large passageways for the movement of air along the interior surface of the roof sheeting. Unfortunately, this wide expanse of unreinforced passageway, particularly when the baffle vent is manufactured from foam or a thin plastic material to maintain cost considerations, is subjected to collapse, especially when used with expanding foam insulation techniques. If the passageway collapses, the baffle vent is not functional to allow the passage of air from the soffit past the insulation layer to the upper portions of the attic structure.
Providing a combination baffle vent and insulation block has been recognized in the prior art. For example, the apparatus disclosed in U.S. Pat. No. 5,007,216, issued to David Pearson on Apr. 16, 1991, is a cardboard device that can be folded and stapled in place between the rafters and tacked to the wall top plate. As with such prior art devices, this baffle and insulation stop combination is intended for installation after the roofing materials have been attached to the rafters. The installation of the Pearson baffle would be cumbersome and time consuming with respect to use in the manufactured housing industry where production speed is essential. Furthermore, such cardboard construction is not sufficiently rigid to consistently withstand the pressures of expanded foam insulation. Other similar prior art combination baffle and insulation stop devices can be seen in U.S. Pat. No. 4,611,443, granted to Ralph H. Jorgensen, et al., on Sep. 16, 1986; in U.S. Pat. No. 4,581,861, granted on Apr. 15, 1986, to Matthew Eury; in U.S. Pat. No. 4,214,510, granted to Bruce Ward on Jul. 29, 1980; in U.S. Pat. No. 4,185,433, granted on Jan. 29, 1980, to James Cantrell; and in U.S. Pat. No. 3,863,553, granted on Feb. 4, 1975, to Bryce Koontz.
In U.S. Pat. No. 6,357,185, issued to Keith Obermeyer, et al., on Mar. 19, 2002, a separate insulation stop member is disclosed as being cooperable with a baffle vent that is stapled to the underside of the roof sheeting to provide a barrier to the movement of insulation into the soffit area and to provide a flow of ventilation air from the soffit into the attic above the insulation layer. As with the combination baffle vent and insulation stop devices noted above, the Obermeyer insulation block is formed for installation after the construction of the roof materials onto the roof rafters. The cardboard insulation block is formed with various fold lines to fit between conventional 16 inch and 24 inch centered rafters and joists and includes staple tabs that fix the insulation block to the interior vertical face of the wall top plate, as well as to the vertical faces of the rafters and joists and the underside of the roof sheeting to fix the insulation block in place to resist the infiltration of insulation into the soffit. Furthermore, the Obermeyer insulation block is shaped to mate with the underside of the corresponding baffle block stapled to the underside of the roof sheeting, thus providing a barrier to insulation and establishing a flow path for ventilation air from the soffit into the attic past the insulation blanket.
Accordingly, it would be desirable to provide an insulation block that would be cooperable with a corresponding baffle vent structure, the combination of which would be particularly adapted for use in the manufactured housing industry to establish and maintain passageways for the movement of air from the building soffit past the insulation layer into the upper attic area for discharge from the attic through a roof vent. It would also be desirable that the baffle vent be formed in a manner to resist collapsing when expanded foam insulation material, or other similar insulation material that exerts a force onto the baffle vent, is installed against the insulation stop.